Hydrogen peroxide stabilizer and preparation method thereof

Abstract

The invention relates to the technical field of chemical engineering, and discloses a hydrogen peroxide stabilizer and a preparation method thereof.The stabilizer is obtained in the mode that alpha-chlorinated acrylic acid and functional monomers are subjected to free radical polymerization and then hydrolyzed; the functional monomer is obtained by firstly carrying out ammonolysis reaction on diethylenetriamine and allyl glycidyl ether to obtain an intermediate, then mixing the intermediate with sodium chloroacetate and carrying out reaction under an alkaline condition, and by introducing the functional monomer containing the carboxylic acid group, the stability of hydrogen peroxide is improved; and invalid decomposition caused by metal ion catalysis is reduced.

Description

Technical Field

[0001] The present application relates to the field of chemical technology, and in particular to a hydrogen peroxide stabilizer and a preparation method thereof. Background Art

[0002] Hydrogen peroxide bleaching is a bleaching method widely used in the pulp and paper industry. It has the advantages of high whiteness after bleaching, low cost, clean and environmentally friendly, good whiteness stability, and easy to achieve closed circulation of production water. In the production process of chemical mechanical pulp (abbreviated as chemical mechanical pulp), hydrogen peroxide bleaching has irreplaceable advantages. The reaction principle of hydrogen peroxide bleaching is as follows: H2O2 generates hydrogen peroxide ions (HOO - ), HOO - It is nucleophilic and can undergo decolorization reactions with chromophores such as carbonyl groups, conjugated double bonds, quinoid structures, or methylene quinones. It also increases the hydrophilicity of the reaction products, allowing them to be removed during subsequent washing. However, during H2O2 bleaching, H2O2 decomposes to form hydroxyl radicals (HO·) and hydroperoxyl radicals (HOO·), both of which react with carbohydrates. HOO· can oxidize reducing end groups of carbohydrates to carboxyl groups. HO· can oxidize both reducing end groups and alcoholic hydroxyl groups to carbonyl groups, forming ketol structures. The oxidation products undergo glycosidic bond cleavage in hot alkaline solutions, thereby degrading the carbohydrates. The oxygen generated by the decomposition of H2O2 can also react with carbohydrates under high-temperature alkaline conditions. Therefore, after H2O2 bleaching, pulp viscosity and strength decrease. If bleaching conditions are harsh and metal ions in the bleaching system are not effectively removed, excessive HO· will be formed during the bleaching process, causing severe degradation of carbohydrates, which in turn affects bleaching effectiveness and pulp quality.

[0003] Poly-α-hydroxy acrylic acid is a commonly used hydrogen peroxide stabilizer. It can inhibit the catalytic decomposition of hydrogen peroxide and improve the stability of hydrogen peroxide. However, during use, the chelating ability of poly-α-hydroxy acrylic acid for metal ions still has room for improvement. In addition, there is a risk of intermolecular esterification between the hydroxyl and carboxyl groups in poly-α-hydroxy acrylic acid, which makes the linear structure of poly-α-hydroxy acrylic acid prone to cross-linking network structure during use, thereby producing gel, which in turn affects the bleaching effect of hydrogen peroxide.

[0004] The problem to be solved by this solution is: how to provide a hydrogen peroxide stabilizer with better metal ion chelating ability. Summary of the Invention

[0005] The purpose of the present application is to provide a hydrogen peroxide stabilizer with a more excellent metal ion chelating ability. The stabilizer is introduced into poly-α-hydroxy acrylic acid by polymerizing a functional monomer with α-chloroacrylic acid. Since the functional monomer contains a carboxylic acid functional group, it can efficiently complex metal ions, thereby reducing the ineffective decomposition of hydrogen peroxide catalyzed by metal ions, and effectively improving the bleaching efficiency of hydrogen peroxide.

[0006] To achieve the above-mentioned purpose, the present application discloses a hydrogen peroxide stabilizer, which is obtained by free radical polymerization of α-chloroacrylic acid and functional monomers followed by hydrolysis;

[0007] The preparation method of the functional monomer specifically comprises the following steps:

[0008] Step 1: adding allyl glycidyl ether dropwise to an aqueous solution of diethylenetriamine at a molar ratio of 1:0.9 to 1 and subjecting the mixture to ultrasonic irradiation to obtain an intermediate;

[0009] Step 2: adding the intermediate dropwise to an aqueous solution of sodium chloroacetate according to the molar ratio of diethylenetriamine to sodium chloroacetate in step 1 of 1:3.8-4, then adding sodium hydroxide solution dropwise to the system and maintaining the pH value of the system at 11-11.5, and obtaining a functional monomer after the reaction is completed.

[0010] Preferably, the mass ratio of the α-chloroacrylic acid to the functional monomer is 100:2-10.

[0011] Preferably, step 1 is specifically as follows: dissolving diethylenetriamine in water at a temperature of 70 to 90° C., then adding allyl glycidyl ether dropwise to the aqueous solution of diethylenetriamine at a molar ratio of allyl glycidyl ether to diethylenetriamine of 1:0.9 to 1 and subjecting to ultrasonic irradiation for 30 to 60 minutes to obtain an intermediate.

[0012] Preferably, step 2 is specifically as follows: according to the molar ratio of diethylenetriamine to sodium chloroacetate in step 1 of 1:3.8-4, the intermediate is added dropwise to the sodium chloroacetate solution, and then sodium hydroxide solution is added dropwise to the system and the pH value of the system is maintained at 11-11.5, and the reaction is carried out at a temperature of 60-70°C for 4-5h to obtain a functional monomer.

[0013] Preferably, the sodium chloroacetate is obtained by reacting chloroacetic acid and sodium hydroxide, and the preparation method of sodium chloroacetate is specifically as follows:

[0014] Chloroacetic acid was dissolved in ethanol, and then sodium hydroxide solution was added dropwise to the chloroacetic acid aqueous solution at a molar ratio of chloroacetic acid to sodium hydroxide of 1:1. The reaction was continued for 0.5 to 1 hour. After the reaction was completed, the mixture was cooled, crystallized, and filtered to obtain sodium chloroacetate crystals.

[0015] In addition, the present application also discloses a preparation method for the above-mentioned hydrogen peroxide stabilizer, wherein α-chloroacrylic acid and a functional monomer are subjected to free radical polymerization, followed by hydrolysis to obtain the hydrogen peroxide stabilizer.

[0016] Preferably, the steps include:

[0017] Step B1: Add α-chloroacrylic acid and functional monomers to water, then add initiator and heat the system to 60-90°C and react for 2-3 hours. After the reaction is complete, cool and filter to obtain a solid product;

[0018] Step B2: adding the solid product to an alkaline solution for hydrolysis to obtain a hydrogen peroxide stabilizer.

[0019] Preferably, the initiator is selected from at least one of ammonium persulfate, potassium persulfate, and sodium persulfate;

[0020] The alkaline solution is a sodium hydroxide solution, and the concentration of sodium hydroxide in the alkaline solution is 1-2 mol / L.

[0021] Preferably, during the hydrolysis process in step B2, the temperature of the system is 70-90°C.

[0022] The beneficial effects of this application are:

[0023] The present application provides a hydrogen peroxide stabilizer with a more excellent metal ion chelating ability. The stabilizer is prepared by polymerizing a functional monomer with α-chloroacrylic acid and introducing it into poly-α-hydroxyacrylic acid. Since the carboxylic acid group contained in the functional monomer can well chelate metal ions, the influence of metal ions on hydrogen peroxide can be reduced, thereby improving the stability of hydrogen peroxide.

[0024] In addition, since the carboxyl group has a certain reactivity with the hydroxyl group in poly-α-hydroxy acrylic acid, the intermolecular esterification part of the poly-α-hydroxy acrylic acid can be converted into intramolecular esterification, thereby reducing the risk of gelation caused by intermolecular esterification during the use of poly-α-hydroxy acrylic acid. DETAILED DESCRIPTION

[0025] The present invention will be described clearly and completely below in conjunction with the examples of the present invention. In the description of the present invention, it should be noted that, where specific conditions are not specified in the examples, conventional conditions or conditions recommended by the manufacturer were used. Reagents or instruments used where the manufacturer is not specified are conventional products that can be purchased commercially.

[0026] It should be noted that the sources of the raw materials used in the examples and comparative examples are as follows:

[0027] α-chloroacrylic acid, CAS number 598-79-8;

[0028] Diethylenetriamine, CAS number 111-40-0;

[0029] Chloroacetic acid, CAS number 79-11-8;

[0030] Allyl glycidyl ether, CAS number 106-92-3;

[0031] Ammonium persulfate, CAS number 7727-54-0;

[0032] Sodium hydroxide, CAS number 1310-73-2.

[0033] Preparation of sodium chloroacetate:

[0034] Chloroacetic acid was dissolved in anhydrous ethanol. After the temperature dropped to below 20°C, sodium hydroxide solution was added dropwise to the system at a molar ratio of chloroacetic acid to sodium hydroxide of 1:1. After the addition was completed, the mixture was reacted for 1 hour to obtain an aqueous solution of sodium chloroacetate. The aqueous solution of sodium chloroacetate was then cooled, crystallized, and filtered to obtain sodium chloroacetate.

[0035] Example 1

[0036] 1.1 Preparation of functional monomers

[0037] Step 1:

[0038] Diethylenetriamine was dissolved in an aqueous solution at a temperature of 80°C at a mass ratio of 1:10, and then allyl glycidyl ether was added dropwise to the diethylenetriamine at a molar ratio of 1:0.95 and ultrasonic irradiation was performed for 40 minutes (during the ultrasonic irradiation, the frequency was 30 kHz and the acoustic power density was 0.15 w / cm 2 ), to obtain an intermediate;

[0039] Step 2: According to the molar ratio of diethylenetriamine to sodium chloroacetate in step 1 of 1:3.9, the intermediate is added dropwise to a sodium chloroacetate aqueous solution (the mass fraction of sodium chloroacetate in the sodium chloroacetate aqueous solution is 70%), and then sodium hydroxide solution is added dropwise to the system and the pH value of the system is maintained at 11 to 11.5. After the reaction is completed, a functional monomer is obtained.

[0040] 1.2 Preparation of hydrogen peroxide stabilizer:

[0041] Step B1: 100 g of α-chloroacrylic acid and 2 g of functional monomer were added to 200 g of water, followed by adding 0.4 g of ammonium persulfate. The system was heated to 60° C. and reacted for 2 h to obtain a solid product.

[0042] Step B2: The solid product is added to a sodium hydroxide solution with a concentration of 1 mol / L for hydrolysis. During the hydrolysis process, the temperature of the system is 70° C. After the hydrolysis is completed, a hydrogen peroxide stabilizer is obtained.

[0043] Example 2

[0044] 1.1 Preparation of functional monomers

[0045] Step 1:

[0046] Diethylenetriamine was dissolved in an aqueous solution at a temperature of 70°C at a mass ratio of 1:10, and then allyl glycidyl ether was added dropwise to the diethylenetriamine at a molar ratio of 1:1 and ultrasonic irradiation was performed for 60 minutes (the frequency of ultrasonic irradiation was 20 kHz and the acoustic power density was 0.1 w / cm 2 ), to obtain an intermediate;

[0047] Step 2: According to the molar ratio of diethylenetriamine to sodium chloroacetate in step 1 of 1:3.8, the intermediate is added dropwise to a sodium chloroacetate aqueous solution (the mass fraction of sodium chloroacetate in the sodium chloroacetate aqueous solution is 70%), and then sodium hydroxide solution is added dropwise to the system and the pH value of the system is maintained at 11 to 11.5. After the reaction is completed, a functional monomer is obtained.

[0048] 1.2 Preparation of hydrogen peroxide stabilizer:

[0049] Step B1: 100 g of α-chloroacrylic acid and 6 g of functional monomer were added to 200 g of water, followed by the addition of 0.4 g of ammonium persulfate. The system was heated to 75° C. and reacted for 2.5 h to obtain a solid product.

[0050] Step B2: adding the solid product to a sodium hydroxide solution with a concentration of 1.5 mol / L for hydrolysis, and during the hydrolysis process, the temperature of the system is 80° C., and after the hydrolysis is completed, a hydrogen peroxide stabilizer is obtained.

[0051] Example 3

[0052] 1.1 Preparation of functional monomers

[0053] Step 1:

[0054] Diethylenetriamine was dissolved in an aqueous solution at a temperature of 90°C at a mass ratio of 1:10, and then allyl glycidyl ether was added dropwise to the diethylenetriamine at a molar ratio of 1:0.9 and ultrasonic irradiation was performed for 30 minutes (during the ultrasonic irradiation, the frequency was 40 kHz and the acoustic power density was 0.2 w / cm 2 ), to obtain an intermediate;

[0055] Step 2: According to the molar ratio of diethylenetriamine to sodium chloroacetate in step 1 of 1:4, the intermediate is added dropwise to a sodium chloroacetate aqueous solution (the mass fraction of sodium chloroacetate in the sodium chloroacetate aqueous solution is 70%), and then sodium hydroxide solution is added dropwise to the system and the pH value of the system is maintained at 11-11.5. After the reaction is completed, a functional monomer is obtained.

[0056] 1.2 Preparation of hydrogen peroxide stabilizer:

[0057] Step B1: 100 g of α-chloroacrylic acid and 10 g of functional monomer were added to 200 g of water, followed by adding 0.4 g of ammonium persulfate and heating the system to 90° C. for 3 h to obtain a solid product;

[0058] Step B2: adding the solid product to a sodium hydroxide solution with a concentration of 2 mol / L for hydrolysis, and during the hydrolysis process, the temperature of the system is 90° C., and after the hydrolysis is completed, a hydrogen peroxide stabilizer is obtained.

[0059] Comparative Example 1

[0060] Preparation of hydrogen peroxide stabilizer:

[0061] Step B1: 100 g of α-chloroacrylic acid was added to 200 g of water, followed by 0.4 g of ammonium persulfate. The system was heated to 90° C. and reacted for 3 h to obtain a solid product.

[0062] Step B2: adding the solid product to a sodium hydroxide solution with a concentration of 2 mol / L for hydrolysis, and during the hydrolysis process, the temperature of the system is 90° C., and after the hydrolysis is completed, a hydrogen peroxide stabilizer is obtained.

[0063] Comparative Example 2

[0064] The process is basically the same as Comparative Example 1, except that 2 g of the functional monomer prepared in Example 1 is added to the hydrogen peroxide stabilizer prepared in Comparative Example 1.

[0065] Performance Testing

[0066] 1.Metal ion chelation performance test

[0067] The metal ion chelating properties of the examples and comparative examples of the present invention were tested using the method for determining the chelating capacity of textile printing and dyeing auxiliaries according to GB / T 21884-2008 as follows:

[0068] Table 1: Metal ion chelation performance test

[0069] Group Calcium chelation value (mg / g) Iron chelation value (mg / g) Example 1 72 53 Example 2 80 58 Example 3 82 59 Comparative Example 1 48 33 Comparative Example 2 52 38

[0070] From the above data, it can be seen that the introduction of carboxylic acid groups into the poly-α-hydroxy acrylic acid molecular chain significantly improves the metal ion chelating performance of poly-α-hydroxy acrylic acid;

[0071] Further observation of Comparative Examples 1-2 shows that when the functional monomer is simply added to poly-α-hydroxy acrylic acid, it can play a certain role in chelating metal ions. However, the improvement in the metal ion chelating ability of Comparative Example 1 is significantly weaker than that of Examples 1-3. It can be seen that simply using the functional monomer together with poly-α-hydroxy acrylic acid is difficult to significantly improve the metal ion chelating ability of the hydrogen peroxide stabilizer.

[0072] 2. Bleaching performance test

[0073] Taking the pulp from the medium-concentration bleaching of the chemical pulp plant, the pulp parameters of the high-concentration bleaching operation are as follows:

[0074] Table 2: Pulp parameters for high-consistency bleaching operation in a chemical-mechanical pulp mill

[0075]

[0076] In addition, in the actual bleaching process of the factory, the bleaching temperature is 90°C and the bleaching time is 60 min;

[0077] Furthermore, the pulp is 100% eucalyptus pulp, the initial brightness of which is 45, and the required brightness is 72.

[0078] To test the effect of the hydrogen peroxide stabilizer (hydrogen peroxide stabilizer) prepared in this case on the whiteness of the pulp during the bleaching process and its ability to stabilize hydrogen peroxide;

[0079] The bleaching performance of stabilized hydrogen peroxide was tested according to the following experimental steps (this bleaching method was designed based on the actual bleaching method of the factory, where the concentrations of alkali, hydrogen peroxide stabilizer, and pulp were calculated in proportion to the actual production method of the factory):

[0080] (1) Weigh a certain amount of pulp into a polyethylene ziplock bag, add a certain amount of dilution water, add the required bleaching reagent according to the amount of reagent required for bleaching, knead for 5 minutes and then put it into a water bath at 90℃ and heat for 60 minutes.

[0081] (2) After bleaching, weigh 11g of slurry in sequence, take two from each bag, add 300g of purified water respectively, and stir and disperse with a blender.

[0082] (3) Stir for 5 minutes and then filter.

[0083] (4) After filtration, the tablets were pressed for 3 minutes and then naturally dried under constant temperature and humidity conditions, and then the whiteness was tested.

[0084] After the pulp in each bag was weighed, the filtrate was squeezed out and the residual hydrogen peroxide was determined.

[0085] Table 3: Stabilization of hydrogen peroxide bleaching performance by stabilizer

[0086] Group Front side whiteness Back side whiteness Average whiteness Hydrogen peroxide residue mg / L Example 1 75.7 75.6 75.65 2.4376 Example 2 77.4 77.0 77.20 3.0179 Example 3 78.1 77.3 77.70 3.1165 Comparative Example 1 70.5 69.6 70.05 1.6235 Comparative Example 2 71.3 70.8 71.05 1.8547

[0087] From the above data, it can be seen that, compared with Comparative Example 1, the whiteness of the pulp and the residual amount of hydrogen peroxide are both improved after using the hydrogen peroxide stabilizers prepared in Examples 1-3 under the same process. It can be seen that, the hydrogen peroxide stabilizers prepared in Examples 1-3 inhibit the ineffective decomposition of hydrogen peroxide caused by metal ions and improve the bleaching efficiency of hydrogen peroxide, thus it is concluded that the introduction of the functional monomer into the molecular chain of poly-α-hydroxy acrylic acid improves the performance of stabilizing hydrogen peroxide. In addition, it can be seen from Comparative Example 2 that, after simply adding the functional monomer to the hydrogen peroxide stabilizer prepared in Comparative Example 1, the whiteness and the residual amount of hydrogen peroxide of Comparative Example 2 are improved to a certain extent, but the improvement is significantly less than that of any one of Examples 1-3, which indicates that, compared with simply physically blending the functional monomer with poly-α-hydroxy acrylic acid, the introduction of the functional monomer into the molecular chain by free radical polymerization according to the method provided in the present application has a more obvious effect of improvement.

[0088] The above examples are the preferred embodiments of the present application, but the embodiments of the present application are not limited by the above examples, and any changes, modifications, substitutions, combinations, simplifications made without departing from the spirit and principles of the present application should be equivalent replacement methods, which are all included in the protection scope of the present application.

Claims

1. A hydrogen peroxide stabilizer, characterized in that The stabilizer is obtained by free radical polymerization of α-chloroacrylic acid and functional monomers followed by hydrolysis; The preparation method of the functional monomer specifically comprises the following steps: Step 1: adding allyl glycidyl ether dropwise to an aqueous solution of diethylenetriamine at a molar ratio of 1:0.9 to 1 and subjecting the mixture to ultrasonic irradiation to obtain an intermediate; Step 2: adding the intermediate dropwise to an aqueous solution of sodium chloroacetate according to the molar ratio of diethylenetriamine to sodium chloroacetate in step 1 of 1:3.8-4, then adding sodium hydroxide solution dropwise to the system and maintaining the pH value of the system at 11-11.5, and obtaining a functional monomer after the reaction is completed.

2. The hydrogen peroxide stabilizer according to claim 1, characterized in that The mass ratio of the α-chloroacrylic acid to the functional monomer is 100:2-10.

3. The hydrogen peroxide stabilizer according to claim 1, characterized in that The step 1 specifically comprises: dissolving diethylenetriamine in water at a temperature of 70 to 90° C., then dropwise adding allyl glycidyl ether to the aqueous solution of diethylenetriamine at a molar ratio of 1:0.9 to 1, and subjecting the solution to ultrasonic irradiation for 30 to 60 minutes to obtain an intermediate.

4. The hydrogen peroxide stabilizer according to claim 1, characterized in that The step 2 specifically comprises: adding the intermediate dropwise to the sodium chloroacetate solution according to the molar ratio of diethylenetriamine to sodium chloroacetate in step 1 of 1:3.8-4, then adding sodium hydroxide solution dropwise to the system and maintaining the pH value of the system at 11-11.5, and reacting at a temperature of 60-70° C. for 4-5 hours to obtain a functional monomer.

5. The hydrogen peroxide stabilizer according to claim 1, characterized in that The sodium chloroacetate is obtained by reacting chloroacetic acid and sodium hydroxide, and the preparation method of sodium chloroacetate is specifically as follows: Chloroacetic acid was dissolved in ethanol, and then sodium hydroxide solution was added dropwise to the chloroacetic acid aqueous solution at a molar ratio of chloroacetic acid to sodium hydroxide of 1:

1. The reaction was continued for 0.5 to 1 hour. After the reaction was completed, the mixture was cooled, crystallized, and filtered to obtain sodium chloroacetate crystals.

6. A method for preparing the hydrogen peroxide stabilizer according to any one of claims 1 to 5, characterized in that: The hydrogen peroxide stabilizer is obtained by free radical polymerization of α-chloroacrylic acid and functional monomers and subsequent hydrolysis.

7. The method for preparing a hydrogen peroxide stabilizer according to claim 6, wherein: The following steps are involved: Step B1: Add α-chloroacrylic acid and functional monomers to water, then add initiator and heat the system to 60-90°C and react for 2-3 hours. After the reaction is complete, cool and filter to obtain a solid product; Step B2: adding the solid product to an alkaline solution for hydrolysis to obtain a hydrogen peroxide stabilizer.

8. The method for preparing a hydrogen peroxide stabilizer according to claim 7, wherein The initiator is selected from at least one of ammonium persulfate, potassium persulfate, and sodium persulfate; The alkaline solution is a sodium hydroxide solution, and the concentration of sodium hydroxide in the alkaline solution is 1-2 mol / L.

9. The method for preparing a hydrogen peroxide stabilizer according to claim 7, wherein: During the hydrolysis process of step B2, the temperature of the system is 70-90°C.

Images